Anatomical distal radius fracture fixation plate with fixed-angle K-wire holes defining a three-dimensional surface

ABSTRACT

A fixation plate includes a set of threaded peg holes adapted to individually receive fixation pegs therethrough and non-threaded alignment holes having a relatively smaller diameter than the peg holes and preferably sized to closely receive a K-wire. The alignment holes are located between the peg holes. One alignment hole is configured for aligning the plate during an osteotomy procedure, while other alignment holes are configured for use after fracture reduction and receive K-wires to temporarily stabilize the fracture and secure the plate to the bone and determine whether pegs inserted through adjacent respective peg holes will be properly located before drilling relatively larger holes for such pegs. The head of the plate has a shape and contour which provides bone support and a low profile which minimizes the potential for soft tissue irritation.

This application is a continuation-in-part of U.S. Ser. No. 10/689,797,filed Oct. 21, 2003, which is a continuation-in-part of U.S. Ser. No.10/664,371, filed Sep. 17, 2003, which is a continuation-in-part of U.S.Ser. No. 10/401,089, filed Mar. 27, 2003, both of which are herebyincorporated by reference herein in their entireties.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates broadly to surgical implants. More particularly,this invention relates to a bone fracture fixation system for distalradius fractures.

2. State of the Art

Fracture to the metaphyseal portion of a long bone can be difficult totreat. Improper treatment can result in deformity and long-termdiscomfort.

By way of example, a Colles' fracture is a fracture resulting fromcompressive forces being placed on the distal radius, and which causesbackward or dorsal displacement of the distal fragment and radialdeviation of the hand at the wrist. Often, a Colles' fracture willresult in multiple bone fragments which are movable and out of alignmentrelative to each other. If not properly treated, such fractures mayresult in permanent wrist deformity and limited articulation of thewrist. It is therefore important to align the fracture and fixate thebones relative to each other so that proper healing may occur.

Alignment and fixation of a metaphyseal fracture (occurring at theextremity of a shaft of a long bone) are typically performed by one ofseveral methods: casting, external fixation, pinning, and plating.Casting is non-invasive, but may not be able to maintain alignment ofthe fracture where many bone fragments exist. Therefore, as analternative, external fixators may be used. External fixators utilize amethod known as ligamentotaxis, which provides distraction forces acrossthe joint and permits the fracture to be aligned based upon the tensionplaced on the surrounding ligaments. However, while external fixatorscan maintain the position of the wrist bones, it may nevertheless bedifficult in certain fractures to first provide the bones in properalignment. In addition, external fixators are often not suitable forfractures resulting in multiple bone fragments. Pinning with K-wires(Kirschner wires) is an invasive procedure whereby pins are positionedinto the various fragments. This is a difficult and time consumingprocedure that provides limited fixation if the bone is comminuted orosteoporotic. Plating utilizes a stabilizing metal plate typicallyplaced against the dorsal side of a bone, and screws extending from theplate into holes drilled in the bone fragments to provide stabilizedfixation of the fragments. However, many currently available platesystems fail to provide desirable alignment and stabilization.

In particular, with a distal radius fracture the complex shape of thedistal radius, including the prominent volar rim of the lunate fossa,relatively flat volar rim of the scaphoid fossa, and the sometimesprominent base of the styloid process should be accommodated.Furthermore, the ligaments extending from the volar side of the distalradius to the intercarpal bones must not be irritated or distressed.Moreover, a fixation device should provide desirable alignment andstabilization of the bone structure proximate the articular surface ofthe distal radius.

SUMMARY OF THE INVENTION

It is therefore an object of the invention to provide an improvedfixation system for distal radius fractures.

It is another object of the invention to provide a distal radius volarfixation system that desirably aligns and stabilizes multiple bonefragments in a fracture to permit proper healing.

It is also an object of the invention to provide a distal radius volarplate system which provides support for articular and subchondralsurfaces.

It is an additional object of the invention to provide a distal radiusvolar plate system which accommodates the anatomical structure of themetaphysis of the distal radius.

It is a further object of the invention to provide a distal radius volarplate system which provides support without interfering with ligamentsand soft tissues near the edge of the articular surface.

In accord with these and other objects, which will be discussed indetail below, a distal radius volar fixation system is provided. Thesystem generally includes a plate intended to be positioned against thevolar side of the radius, a plurality of bone screws for securing theplate to the proximal fragment of the radius bone, a plurality of bonepegs sized to extend from the plate and into bone fragments at themetaphysis of a radius bone, and one or more K-wires to facilitatealignment and fixation of the plate over the bone and guide the processof application. Preferred bone pegs and peg holes within the plate areprovided which facilitate entry and retention of the bone pegs withinthe peg holes.

The plate is generally T-shaped, defining an elongate body and agenerally transverse head angled upward relative to the body, andincludes a first side which is intended to contact the bone, and asecond side opposite the first side. The body includes a plurality ofcountersunk screw holes for the extension of the bone screwstherethrough, and optionally one or more substantially smaller K-wirealignment holes. The lower surfaces of the radial and ulnar sideportions of the head are contoured upward (in a Z direction) relative tothe remainder of the head to accommodate the prominent volar rim of thelunate fossa, the relative flat volar rim of the scaphoid fossa and theprominent ridge at the base of the styloid process. An extension isprovided at the head portion along the distal ulnar side of the head tobuttress the volar lip (marginal fragment) of the lunate fossa of theradius bone, thereby providing support to maintain the wrist within thearticular socket in case of fracture of this very essential area.Moreover, the contoured shape provides a stable shape that preventsrocking of the plate on the bone and maintains anatomical alignmentbetween the fracture fragments. The upper and lower surfaces arechamfered to have a reduced profile that limits potential interface withligaments and soft tissues near the edge of the lunate fossa. The headincludes a plurality of threaded peg holes for receiving the pegstherethrough. The peg holes are arranged into a first set provided in aproximal portion of the head, and a second relatively distal setpreferably provided in the tapered portion of the head.

The first set of the peg holes is substantially linearly arrangedgenerally laterally across the head. The line of pegs is preferablyslightly oblique relative to a longitudinal axis through the body of theplate. Axes through the first set of holes are preferably obliquerelative to each other, and are preferably angled relative to each otherin two dimensions such that pegs inserted therethrough are similarlyobliquely angled relative to each other. The pegs in the first set ofpeg holes provide support for the dorsal aspect of the subchondral bonefragments.

The second set of peg holes is provided relatively distal of the firstset. The holes of the second set, if more than one are provided, areslightly out of alignment but generally linearly arranged. The pegs inthe second set of peg holes provide support for the volar and centralaspects of the subchondral bone, behind and substantially parallel tothe articular bone surface.

A distal alignment hole is provided generally between two peg holes ofthe second set of peg holes. At the upper surface of the plate, thedistal alignment hole is substantially circular, while at the lowersurface, the hole is laterally oblong. One or more proximal alignmentholes of a size substantially smaller than the peg holes are providedsubstantially along a distal edge defined by a tangent line to shafts ofpegs inserted in the first set of peg holes, and facilitates temporaryfixation of the fracture fragments and of the plate to the bone withK-wires. Furthermore, along the body two longitudinally displacedalignment holes are also provided. All of the alignment holes are sizedto closely receive individual K-wires.

The plate may be used in at least two different manners. According to afirst use, the surgeon reduces a fracture and aligns the platethereover. The surgeon then fixes the elongated body portion of theplate to the proximal radius fragment and then drills K-wires throughthe proximal row of alignment holes on the head portion of the plate totemporarily fix the orientation of the head of the plate to the distalfragment. Once the alignment is so fixed, the fracture is examined,e.g., under fluoroscopy, to determine whether the fracture is reduced inan anatomically correct manner and if the K-wires are properly alignedrelative to the articular surface. As the axes of the proximal alignmentholes closely correspond to axes of adjacent peg holes and the distaledges of the K-wires closely corresponds to the distal edges of theadjacent pegs, the fluoroscopically viewed K-wires provide an indicationas to whether the pegs will be properly oriented in relation to thesubchondral bone of the distal fragment. If the placement is correct,the K-wires maintain the position of the plate over the fracture. Thepeg holes may then be drilled with confidence that their locations andorientations are proper. If placement is not optimal, the K-wires can beremoved and the surgeon has an opportunity to relocate and/or reorientthe K-wires and drill again. Since each K-wire is of relatively smalldiameter, the bone is not significantly damaged by the drilling processand the surgeon is not committed to the initial drill location and/ororientation.

According to a second use, the plate may be used to correct ametaphyseal deformity (such as a malunited fracture or congenitaldeformity). For such purposes, a K-wire is drilled, e.g., underfluoroscopy, into the bone immediately underneath and parallel to thearticular surface in the lateral view until one end of the K-wire islocated within or through the bone and the other end is free. The freeend of the K-wire is guided through the distal oblong alignment hole ofthe head of the plate, and the plate is slid down over the K-wire intoposition against the bone. The oblong alignment hole permits the plateto tilt laterally over the K-wire to sit flat on the bone, but does notpermit movement of the plate over the K-wire in the anterior-posteriorplane. The surgeon drills holes in the bone in alignment with the pegholes and then fixes the plate relative the bone with pegs. The bone isthen cut, and the body of the plate is levered toward the shaft of thebone to re-orient the bone. The body of the plate is then fixed to theshaft to correct the anatomical defect.

Additional objects and advantages of the invention will become apparentto those skilled in the art upon reference to the detailed descriptiontaken in conjunction with the provided figures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a radial side elevation of a right-hand volar plate accordingto the invention, shown with pegs coupled thereto;

FIG. 2 is an ulnar side elevation of a right-hand volar plate accordingto the invention, shown with pegs coupled thereto;

FIG. 3 is top view of a right-hand volar plate according to theinvention, shown with pegs and screws;

FIG. 4 is bottom view of a right-hand volar plate according to theinvention, shown with pegs coupled thereto;

FIG. 5 is a perspective view of a right-hand volar plate according tothe invention, shown with pegs coupled thereto and K-wires extendingthrough body portion alignment holes and through proximal head alignmentholes;

FIG. 6 is a front end view of a right-hand volar plate according to theinvention, shown with pegs coupled thereto and K-wires extending throughbody portion alignment holes and proximal head alignment holes;

FIGS. 7 through 12 illustrate a method of performing an osteotomy of thedistal radius according to the invention;

FIG. 13 is a side elevation of a partially threaded peg according to theinvention;

FIG. 14 is a schematic illustration of a peg coupled within a peg hole;

FIG. 15 is a broken volar view of the distal portion of a left-handvolar plate coupled on a volar side of a distal radius bone according tothe invention; and

FIG. 16 is a broken ulnar side view of the distal portion of a left handvolar plate coupled on a volar side of a distal radius bone according tothe invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Turning now to FIGS. 1 through 6, a fracture fixation system 100according to the invention is shown. The system 100 is particularlyadapted for aligning and stabilizing multiple bone fragments in adorsally displaced distal radius fracture (or Colles' fracture). Thesystem 100 generally includes a substantially rigid T-shaped plate 102,commonly called a volar plate, bone screws 104 (FIG. 3), pegs 106, 108,and K-wires 110 (FIGS. 5 and 6). Pegs 106 have a threaded head and anon-threaded shaft, and pegs 108 have both a threaded head and athreaded shaft. Either pegs 106 or 108, or a combination thereof may beused at the discretion of the surgeon. Exemplar pegs are described inmore detail in U.S. Pat. No. 6,364,882, which is hereby incorporated byreference herein in its entirety.

In addition, a preferred partially threaded shaft peg 108 is shown bestin FIGS. 6 and 13. Peg 108 includes a head portion 200 with preferably asingle helical machine thread 202 of a first pitch and a shaft 204portion having one or more threads 206 of a larger second pitch. (Thehead portion of non-threaded shaft pegs 106 also preferably includes asingle helical thread.) The threads 206 preferably extend along a distalportion 208 of the shaft 204, and most preferably where such distalportion comprises approximately one-half the length of the shaft.Alternatively, or in addition, one or more pegs may be used where thethreads extend along substantially the entirety, or the entirety, or thelength of the shaft.

The volar plate 102 shown in FIGS. 1-6 is a right-hand plate intended tobe positioned against the volar side of a fractured radius bone of theright arm. It is appreciated that a left-hand volar plate (as shown inFIGS. 15 and 16) is substantially a mirror image of the plate shown andnow described. The T-shaped plate 102 defines an elongate body 116, anda head 118 angled upward (in the Z-direction) relative to the body. Theangle a in the Z-direction between the head 118 and the body 116 ispreferably approximately 25°. The head 118 includes a distal buttress120 (i.e., the portion of the head distal a first set of peg holes 134,discussed below), which tapers in thickness toward a distal edge 121.The thickest portion of the plate 102 has a thickness of preferablyapproximately 0.1 inch (2.5 mm), and is preferably made from a titaniumalloy, such as Ti-6Al-4V.

Referring to FIG. 4, the body 116 includes four preferably countersunkscrew holes 124, 125, 126, 127 for the extension of bone screws 104therethrough (FIG. 2). One of the screw holes, 127, is preferablygenerally oval in shape permitting longitudinal movement of the plate102 relative to the shaft of a bone screw when the screw is not tightlyclamped against the plate. The screw holes may be any hole type forattaching a fixation structure, threaded or non-threaded, for coupling acortical screw or a locking peg relative to the plate and the underlyingbone.

Referring to FIGS. 3 and 4, according to one preferred aspect of theplate 102, the head portion 118 includes a proximal first set ofthreaded preferably cylindrical peg holes 134 (for placement of pegs 106and/or 108 therein) and a relatively distal second set of threadedpreferably cylindrical peg holes 138 (for placement of pegs 106 and/or108 therein). Referring to FIG. 14, the peg holes 134, 138 optionallyhave double lead internal threads 210, 212, with entries to thesethreads located 180° apart. Each of the threads 210, 212 is adapted tomate securely with the thread 202 on a peg head 200, however thread 202can only mate with one of the threads 210, 212 at any one time. Thedepth of each of the double lead internal threads 210, 212 is preferablysubstantially less than the depth of thread 202 on peg head 200, andmost preferably approximately one half such depth. The double leadthreads 210, 212 facilitate alignment and entry of the peg head thread202 into a thread of the peg hole, as the peg will require rotation byat most 180° in a single rotational direction before thread engagement.Furthermore, in distinction from a conical head and hole, thecylindrical double lead thread hole does not compromise the secureinterlock attained from full travel of the thread 202 of the peg head200 through the cylindrical peg hole 134, 138 through, e.g., 900°.Moreover, the combination of double lead thread holes and a singlehelical thread on the peg head reduces cross-threading by fifty percent.

Referring back to FIGS. 3 and 4, the peg holes 134 of the first set arearranged substantially parallel to a line L₁ that is preferably slightlyskewed (e.g., by 5°-10°) relative to a perpendicular P to the axis A ofthe body portion 116. Axes through the first set of peg holes (indicatedby the pegs 106 extending therethrough) are preferably oblique relativeto each other, and are preferably angled relative to each other in twodimensions, generally as described in commonly-owned U.S. Pat. No.6,364,882, which is hereby incorporated by reference herein in itsentirety. More particularly, the pegs 106 are angled so as to extendthrough the subchondral bone just below and parallel to the curvingarticular surface of the distal radius so as to provide support for thecentral and/or dorsal aspects of the subchondral bone. This obliqueorientation of the pegs operates to stabilize the central and/or dorsalaspects of the subchondral bone of the articular surface relative to thehead 118 of the plate 102 even where such pegs 106 do not have threadedshafts.

The second set of peg holes 138 is provided relatively distal of thefirst set of peg holes 134 and is most preferably primarily located inthe tapered buttress 120. Each of the peg holes 138 preferably definesan axis that is oblique relative to the other of peg holes 136 and 138.Thus, each and every peg 106, 108 when positioned within respective pegholes 134, 138 defines a distinct axis relative to the other pegs.Moreover, the axes of the peg holes 138 are preferably oriented relativeto the axes of peg holes 134 such that pegs 106, 108 within peg holes138 extend (or define axes which extend) between pegs (or axes thereof)within peg holes 134 in an interleaved manner and provide support forvolar aspects of the subchondral bone of the distal radius. The obliqueorientation of the pegs provides such stabilization even where such pegs106 do not have threaded shafts.

Referring specifically to FIGS. 1, 2, 5, 6, 15 and 16, according toanother preferred aspect of the plate 102, in order to approximate theanatomy for ideal fracture support and maintain a low profile, the upperand lower surfaces 140, 142, respectively of the buttress 120 arecontoured relative to provide the least amount of interference with theanatomy. The lower surface 142 is contoured for the anatomical structureof the radius bone 900 that it will overlie. In particular, the lowersurface 142 at an ulnar-side portion 144 of the head portion 118 iselevated primarily in a distal direction to accommodate the bulky volarrim 902 of the lunate fossa 904 (such volar rim commonly separating tobecome a volar marginal fragment in many fractures), and the lowersurface at a radial side portion 146 of the head 118 is elevatedlaterally relative to the remainder of the head to accommodate aprominence 906 at the radial aspect of the radius bone, as indicated bythe visibility of these lower surfaces in the side views of FIGS. 1, 2and 16 and the head-on view of FIG. 6. The contoured shape (withgenerally three defined planes) provides a stable shape that preventsrocking of the plate on the bone.

In addition, the upper and lower surfaces 140, 142 are contoured topresent a reduced profile and therefore limit potential interferencewith the tendons and soft tissue near the edge of the articular surface.To that end, the buttress 120 is tapered to prevent irritation oftendons and soft tissue extending over a boney ridge (referred to hereinas ‘the watershed line’) and identified by dark line 910 on the volarside of the radius where the slope of the bone changes from ascending(up from the diaphysis 912) to descending (the distal articular portion904 of the radius). On the proximal (or ascending) portion of the bonyridge there exists a concavity 916 in the radius bone, and the head 118of the plate 102 is contoured to seat at least partially within theconcavity with the tapered buttress 120 terminating below the boneyridge so that the tendons and soft tissues can move over the boney ridgewithout any interference from the plate. In accord with accommodatingthe anatomy, the tapered edge 121 of the buttress 120 taperssubstantially from the bone contacting surface along the ulnar side ofthe buttress (with a relatively shallow change in slope from theproximal portion of the head to the distal edge of the buttress) andsubstantially tapers from the upper surface along the radial side (witha relatively steeper change in slope from the proximal portion of thehead to the distal edge of the buttress). The distal edge 121 of thebuttress 120 defines ail elongate S-shape on a right-hand plate, anelongate Z-shape on a left-hand plate.

A distal extension 148 is also provided at the ulnar side portion 146 ofthe plate to further buttress the volar rim 902 of the articular socketof the radius bone, thereby providing support to maintain the wristwithin the articular socket. This is contrary to prior art plates which,if they provide laterally asymmetrical support, provide such additionalsupport on the radial side due to the apparent radial extension of theradius in view of the styloid process 914. However, the styloid process914 is on the descending side of the boney ridge 910 (discussed above)and not suitable for buttressing. (According to the present invention,the styloid process 914 is captured by one of the pegs.) The radius bone900 on the ascending side has an enlarged area at the ulnar side at thevolar rim 902 which the distal extension 148 buttresses. In particular,the proximal portion of the head portion 118 (rear of the buttress 120to the proximal edge of the head portion) is approximately 5.3 mm deep,while the distal edge of the buttress is not straight so that thebuttress has a varying proximal-distal depth. From a proximalmostlocation of the buttress 120 aligned with the radialmost hole of thefirst set of peg holes 134 the buttress has a proximal-distal depth of2.28 mm (where the head portion rounds off), from a proximalmostlocation of the buttress aligned with the adjacent hole of the first setof peg holes the buttress has a proximal-distal depth of approximately2.8 mm (along a straight portion substantially parallel to line L₁),from a proximalmost location of the buttress aligned with the adjacenthole thereof of the first set of peg holes the buttress has aproximal-distal depth of 3.56 mm (along an approach to the ulnarsupport), and from a proximalmost location of the buttress aligned withthe ulnarly located hole of the first set of peg holes the buttress hasa proximal-distal depth of 4.57 mm (at the distal extension 148).

Referring specifically to FIGS. 3 and 4, according to a furtherpreferred aspect of the invention, the plate 102 is provided with bodyalignment holes 150 and proximal head alignment holes 152 a, 152 b, 152c (generally 152), each sized to ‘closely accept’ standard Kirschnerwires (K-wires), e.g., 1.55 mm in diameter, in at least in dimension. By‘closely accept’ it is meant that when a K-wire is inserted into any ofthe alignment holes, the K-wire is generally in a fixed anglerelationship with the alignment hole such that there is preferably lessthan five degrees (5°) of relative angular movement therebetween, andmore preferably less than three degrees (3°) of relative angularmovement therebetween. In order to effect such fixed angle relationship,the clearance between the K-wire and the alignment hole is preferably0.002 inch, and more preferably 0.001 inch.

The plate 102 also includes a distal head alignment hole 154 is providedbetween the central and radial-side peg holes 138, and preferably has acircular upper opening, and flares to a laterally oblong lower opening,as shown best in FIG. 6. In view thereof, the alignment hole 154 closelyaccepts a K-wire in a proximal-distal dimension and permits a degree ofangular movement relative thereto in a lateral dimension (preferablyapproximately 30°). Alternatively, the upper opening can be oblong andthe lower opening circular. As yet another alternatively, alignment hole154 can be laterally oblong at upper and lower portions or throughout,but proximally-distally dimensioned to closely receive a K-wire. Thatis, while a K-wire can be angled within the oblong portion of the hole,the close fitting walls are of sufficient length to hold a K-wire in afixed angle relationship relative to the walls. The distal headalignment hole 154 has specialized application in the correction ofmetaphyseal deformities, as described in more detail below.

The upper openings of all the alignment holes 150, 152, 154 aresubstantially smaller in diameter (e.g., by thirty to fifty percent)than the shafts of screws 104 (approximately 3.15 mm in diameter) andthe shafts of pegs 106, 108 (approximately 2.25 mm in diameter).

The body alignment holes 150 are longitudinally displaced along the bodyportion 116 and provided at an oblique angle (preferably approximately15°, as shown in FIG. 5) relative to a line normal relative to the lowersurface 158 of the body portion 116. Alternatively, the body alignmentholes 150 may be oblong in the transverse direction but fixed angle inthe longitudinal direction. This enables the surgeon to drillperpendicular to the bone surface.

The proximal head alignment holes 152 alternate with the peg holes 134.A tangent line H to the distalmost points of the head alignment holes152 is preferably substantially coincident or closely parallel with aline tangent to points on the circumferences of the shafts of pegs 106inserted through holes 134 adjacent the head portion 118 of the plate102. With respect to the proximal head alignment holes, it isappreciated that a shaft 106 a of a peg is generally smaller in diameterthan a head 106 b of a peg (FIG. 6). Thus, a line tangent to the pegholes 134 (each sized for receiving the head 106 b of peg 106) will beclosely located, but parallel, to a line tangent to a distalmost pointon the respective alignment hole 152. Nevertheless, for purposes of theclaims, both (i) a tangent line which is preferably substantiallycoincident with a line tangent to points on the circumferences of theshafts of pegs and (ii) a tangent line to a set of peg holes shall beconsidered to be “substantially coincident” with a line tangent to adistalmost point of an alignment hole 152. Axes through alignment holes152 preferably generally approximate (within, e.g., 3-5°) the angle ofan axis of an adjacent peg hole 134. Moreover, the axis through eachproximal alignment hole 152 is preferably oriented substantiallyequidistantly between the axes through peg holes 134 on either side ofthe alignment hole. As such, K-wires 110 inserted into the proximalalignment holes 152 (and extending coaxial with the axes therethrough)define a virtual surface which approximately substantially the samevirtual surface defined by pegs 106, 108 inserted through peg holes 134.This common virtual surface follows the dorsal aspect of the subchondralbone. Thus, as described in more detail below, the insertion of K-wires110 through proximal alignment holes 152 in the plate 102 provides avisual cue to the surgeon which anticipates the location of subsequentlyplaced pegs 106, 108.

The plate 102 may be used in at least two different applications:fracture fixation and metaphyseal osteotomies. In either application, anincision is first made over the distal radius, and the pronatorquadratus is reflected from its radial insertion exposing the entiredistal radius ulnarly to the distal radioulnar joint. For fracturefixation, the surgeon reduces the fracture and aligns the plate 102thereover. The surgeon then either attaches the plate to the proximalfragment with a screw or drills one or two K-wires 110 throughrespective body alignment holes 150, and one or more K-wires throughselected proximal head alignment holes 152 at the location at which thesurgeon believes the pegs 106, 108 should be placed based on anatomicallandmarks and/or fluoroscopic guidance. The K-wires temporarily fix theorientation of the plate to the distal fragment. While the fixation istemporary, it is relatively secure in view of the fact that the bodyalignment holes 150, proximal head alignment holes 152, and K-wires 110therethrough are angled in different orientations relative to the lowersurface of the plate. The K-wires 110 not only fix the plate 102 to thebone, but also prevent angular displacement of bone fragments. Once thealignment is so fixed, the fracture is examined, e.g., underfluoroscopy, to determine whether the K-wires 110 are properly alignedrelative to the articular surface. As the axes of the proximal headalignment holes 152 correspond to axes of the adjacent peg holes 134,the fluoroscopically viewed K-wires 110 anticipate whether the pegs 106,108 will be properly oriented. If the placement is correct, the K-wires110 maintain the position of the plate 102 over the fracture while holesin the bone are drilled through the screw holes 124, 125, 126, 127 forthe screws 104 and peg holes 134, 138 for pegs 106, 108, with confidencethat the locations and orientation of the screws and pegs insertedtherein are anatomically appropriate. In addition, where pegs 108 areused, due to the difference in pitch between the head threads 202 andshaft threads 206, slight compression of a distally or dorsallydisplaced fragment toward a proximal fragment or bone (e.g., 1.5 mm oftravel) is effected even though the head 200 will lock relative to thehead 118 of the plate 100. Once the screws 104 and pegs 106, 108 havesecured the plate to the bone, the K-wires are preferably removed.

If fluoroscopic examination indicates that placement of the K-wires 110is not optimal, the K-wires can be removed and the surgeon has anopportunity to relocate and/or reorient the K-wires and drill again.Since each K-wire is of relatively small diameter, the bone is notsignificantly damaged by the drilling process and the surgeon is notcommitted to the initial drill location and/or orientation.

The pegs 106 within the pegs holes 134 define projections that providesupport at the central and/or dorsal aspects of the subchondral bone.The pegs 106 within peg holes 138 define projections that providesupport at the volar aspect behind the articular surface of the bonesurface. The sets of pegs 106, 108 through peg holes 134, 138 laterallyoverlap so that the pegs preferably laterally alternate to provideclosely-spaced tangential cradling of the subchondral bone. A preferreddegree of subchondral support is provided with four peg holes 134 (andassociated pegs) through the proximal portion of the head 118 of theplate, and three peg holes 138 (and associated pegs) through the distalportion of the head 118. The fracture fixation system thereby defines aframework which substantially tangentially supports the bone fragmentsin their proper orientation. In accord with an alternate less preferredembodiment, suitable support may also be provided where the pegs 106 and108 are parallel to each other or in another relative orientation orwith fewer peg holes and/or pegs.

The method particularly facilitates stabilization of a metaphysealfracture which may include a smaller distal bone fragment spaced apartfrom a larger proximal fragment. The insertion of one or more threadedpegs 108 (preferably in conjunction with several non-threaded pegs 106)in which the threads on the shaft 206 have a pitch greater than thethreads 202 on the head 200 causes a limited amount of compression ofthe smaller distal bone fragment toward the larger proximal bonefragment, and thus toward the plate.

According to a second use, the plate may be used in an osteotomy tocorrect a metaphyseal deformity 200 (such as malformed fracture orcongenital deformity), as shown in FIG. 7. For such purposes, a K-wire110 is drilled into the bone parallel to the articular surface S in thelateral view under fluoroscopy (FIG. 8). The free end of the K-wire 110is guided through the oblong distal head alignment hole 154, and theplate 102 is slid down over the K-wire into position against the bone(FIG. 9). The oblong alignment hole 154 permits the plate 102 to tiltlaterally over the K-wire 110 to sit flat on the bone, but does notpermit tilting of plate relative to the K-wire in the anterior-posterior(sagital) plane. This is important, as visualization to align the K-wireparallel relative to the articular surface will not disclose whether theK-wire is angled in the lateral direction. Thus, the plate is broughtover the K-wire in the correct anterior-posterior alignment, but maythen be laterally titled on the K-wire to effect proper medial-lateralplacement of the plate on bone. Once the plate 102 is seated against thebone, the surgeon drills holes in the bone in aligmnent with the pegholes 134, 138 (FIG. 3) and then fixes the plate relative the bone withpegs 106, 108 (FIG. 10). The K-wire 110 is removed. The bone is then sawcut at 202 proximal the location of the head 118 of the plate 102 (FIG.11), and the body 116 of the plate is levered toward tie proximaldiaphyseal bone 204, creating an open wedge 206 at the deformity (FIG.12). When the body 116 of the plate 102 is in contact and longitudinalalignment with the diaphysis of the bone, the bone distal of the cut hasbeen repositioned into the anatomically correct orientation relative tothe shaft of the bone. The body 116 of the plate 102 is then secured tothe bone with screws 104. Post-operatively, the open wedge in the boneheals resulting in an anatomically correct distal radius.

While fixed single-angle pegs have been disclosed for use with the plate(i.e., the pegs may be fixed in respective threaded peg holes 134, 136only coaxial with an axis defined by the respective peg holes), it isappreciated that an articulating peg system, such as that disclosed inco-owned U.S. Pat. No. 6,440,135 or co-owned and co-pending U.S. Ser.No. 10/159,612, both of which are hereby incorporated by referenceherein in their entireties, may also be used. In such articulating pegsystems, the peg holes and pegs are structurally adapted such thatindividual pegs may be fixed at any angle within a range of angles. Inaddition, while less preferable, one or both sets of the pegs may bereplaced by preferably blunt tines which are integrated into the platesuch that the plate and tines are unitary in construct. Similarly, otherelongate projections may be coupled to the plate to define the desiredsupport.

There have been described and illustrated herein embodiments of afixation plate, and particularly plates for fixation of distal radiusfractures, as well as a method of aligning and stabilizing a distalradius fracture and performing an osteotomy. While particularembodiments of the invention have been described, it is not intendedthat the invention be limited thereto, as it is intended that theinvention be as broad in scope as the art will allow and that thespecification be read likewise. Thus, while particular preferredmaterials, dimensions, and relative angles for particular elements ofthe system have been disclosed, it will be appreciated that othermaterials, dimensions, and relative angles may be used as well. Further,plates having shapes other than a ‘T’ may also be used, such as lateraland medial columns (generally ‘L’-shaped), and plates having a flaredhead, provided such plates are dimensioned and configured for placementat the distal radius. In addition, while a particular number of screwholes in the volar plate and bone screws have been described, it will beunderstood another number of screw holes and screws may be used.Further, fewer screws than the number of screw holes may be used tosecure to the plate to the bone. Also, fewer or more peg holes and bonepegs may be used, preferably such that at least two pegs angled in twodimensions relative to each other are provided. In addition, while aparticular preferred angle between the head and body has been disclosed,other angles can also be used. Moreover, while the cylindrical doublelead thread hole and single thread head interface has been disclosedwith respect to a fracture plate for distal radius fractures, it isappreciated that such a system has advantage to other orthopedicstabilization devices such as fragment plates (which may be rectangularin shape or a different shape) and plates specifically designed forfractures of other bones. Similarly, a threaded peg (i.e., lockingscrew) with threads of different pitches on the head and along the shaftmay also be used in other applications. Furthermore, while a double leadthread is preferred for use with a peg having a single thread on itshead, it is appreciated that, e.g., a triple lead thread can be usedwhere the entry leads are angularly offset by 120°. Such will reducecross threading by two-thirds, but will also reduce hole thread depthfurther. It will therefore be appreciated by those skilled in the artthat yet other modifications could be made to the provided inventionwithout deviating from its spirit and scope.

1. A fixation plate for use with a plurality of fixation pegs andK-wires, comprising: a substantially rigid plate having a bonecontacting surface and defining a first set of peg holes eachstructurally adapted to engage a fixation peg with a threaded head andretain the fixation pegs in a fixed angle relationship such that thefixation pegs are obliquely oriented in at least one dimension relativeto each other, and a first plurality of non-threaded alignment holessubstantially smaller in diameter than said first set of peg holes, eachof said alignment holes sized to closely receive a K-wire such that theK-wires will be in a fixed angle relationship relative to said plate,said alignment holes positioned in said plate and having predefinedaxial orientations such that when a plurality of the K-wires areinserted into said alignment holes, the K-wires approximate a threedimensional surface defined by fixation pegs inserted into said pegholes.
 2. A fixation plate according to claim 1, wherein: said alignmentholes and alternately arranged with said peg holes.
 3. A fixation plateaccording to claim 1, wherein: said alignment holes are laterallydisplaced relative to said peg holes.
 4. A fixation plate according toclaim 1, wherein: said each of said peg holes is threaded.
 5. A fixationplate according to claim 1, wherein: said first set of peg holesincludes at least three peg holes.
 6. A fixation plate according toclaim 5, wherein: said first set of peg holes are substantially linearlyarranged.
 7. A fixation plate according to claim 1, wherein: said platedefines a second set of peg holes each structurally adapted to engage afixation peg with a threaded head, said second set longitudinallydisplaced relative said first set.
 8. A fixation plate according toclaim 7, wherein: said first set of peg holes includes at least four pegholes.
 9. A fixation plate according to claim 7, wherein: said plateincludes a body portion and a head portion angled in a Z-directionrelative to said body portion, wherein said first and second sets of apeg holes are in said head portion.
 10. A fixation plate according toclaim 9, wherein: said head portion includes a distal buttress portionwhich tapers in thickness from an upper surface toward a bone contactingsurface.
 11. A fixation plate according to claim 10, wherein: saidbuttress portion is provided distal of said first set of peg holes, andeach of said peg holes of said second set is at least partially providedin said buttress portion.
 12. A system for fracture fixation of thedistal radius, comprising: a) a plate having a body portion and a headportion angled relative to said body portion, said body portion definingat least one screw hole, and said head portion defining a plurality ofpeg holes each structurally adapted to engage a fixation peg with athreaded head and at least one substantially smaller non-threadedalignment hole; b) a plurality of pegs each having a threaded head and ashaft, said pegs sized for insertion into said peg holes; and c) atleast one K-wire, wherein said alignment hole is sized to closelyreceive said K-wire, such that each K-wire is in substantially in afixed angle relationship with an alignment hole in which it is received.13. A fixation system according to claim 12, wherein: said K-wirethrough an alignment hole toggles by no more than 5° relative to saidplate.
 14. A fixation system according to claim 13, wherein: said K-wirethrough an alignment hole toggles by no more than 3° relative to saidplate.
 15. A fixation system according to claim 12, wherein: a clearanceof not more than 0.002 inch is provided between said K-wire and saidalignment hole.
 16. A fixation system according to claim 12, wherein: aclearance of approximately 0.001 inch is provided between said K-wireand said alignment hole.